Receiving apparatus, receiving method, and supplying medium

ABSTRACT

Digital television broadcast signals are received and AV signals are reproduced in a common apparatus. A digital television signal is received and is separated into a compressed first video signal, a compressed first audio signal, and first copyright protection information. An AV signal is reproduced from a recording medium and is separated into a second compressed video signal, a second compressed audio signal, and second copyright protection information. The first signals and information are selected when a received operation command is a command to select the digital television broadcast channel, and the second signals and information are selected when the received operation command is a command to reproduce data. The selected signals and information are decoded to generate a decoded video signal, a decoded audio signal, and a copyright protection signal, and the copyright protection signal is added to the decoded signals to limit copying.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.09/531,730, filed Mar. 21, 2000, the disclosure of which is herebyincorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to a receiving apparatus, a receivingmethod, and a supplying medium, and more particularly to a receivingapparatus, a receiving medium, and a supplying medium having thecapability of reproducing DVD (digital versatile disc) video data.

In recent years, DVD players for reproducing DVD videos have becomecommercially available. Audio Visual (AV) data recorded on DVD videodiscs is coded in a compressed form according to the MPEG (MovingPicture Experts Group)-2 standard. Therefore, DVD players have thecapability of decoding the AV data into a decompressed form.

Receiving apparatus for receiving satellite digital broadcasts (such asSky Perfect TV (trademark)) are now becoming popular. AV data ofsatellite digital broadcasts is supplied also in the compressed formaccording to the MPEG-2 standard. Therefore, receiving apparatus forreceiving broadcast programs have the capability of decompressingcompressed AV data.

The MPEG-2 standard will be adopted in terrestrial digital broadcastingwhich will begin in the near future, and receiving apparatus thereforwill also have the capability of decoding AV data into a decompressedform.

However, if a certain user wants to enjoy both AV data recorded on DVDvideo discs and digital broadcast programs (satellite or terrestrialdigital broadcasts), the user has to have both a DVD player and a settop box (apparatus for receiving digital broadcasts). Thus, the cost andthe installation space become large because two devices are required.

Furthermore, to display the outputs of both the DVD player and the settop box on the same television receiver, complicated connections andoperations are required.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a technique forrealizing a small-sized low-cost receiving apparatus capable ofreceiving digital television broadcasts and also capable of reproducingDVD video discs using the same means for decoding data compressed inaccordance with the MPEG-2 standard.

According to the present invention, there is provided a readable mediumrecorded with instructions for carrying out a method for receivingdigital television broadcast signals and reproducing AV signals in acommon apparatus. The method includes receiving at least one operationcommand provided by a user; determining whether the received operationcommand is a command to select a digital television broadcast signal ora command to reproduce data; when the received operation command is acommand to select a digital television broadcast channel, a digitaltelevision broadcast signal is received and is separated into a firstvideo signal coded in a compressed form according to a predeterminedmethod, a first audio signal coded in the compressed form, and firstcopyright protection information; when the received operation command isa command to reproduce data, an AV signal is reproduced from a recordingmedium and is separated into a second video signal coded in thecompressed form, a second audio signal coded in the compressed form, andsecond copyright protection information; the first video signal, thefirst audio signal, and the first copyright protection information areselected when the received operation is the command is the command toselect the digital television broadcast channel, and the second videosignal, the second audio signal, and the second copyright protectioninformation are selected when the received operation command is thecommand to reproduce data; the selected video signal, the selected audiosignal and the selected copyright protection information are decoded togenerate a decoded video signal, a decoded audio signal, and a copyrightprotection signal; and the copyright protection signal is added to thedecoded video signal and to the decoded audio signal to limit thecopying of the decoded video signal and the decoded audio signal.

In the readable medium according to the present invention, as describedabove, a decoder is used in common for both a television broadcastsignal and an AV signal reproduced from a DVD video disc, and thus it ispossible to reduce the cost and the installation space of the receivingapparatus which is also capable of reproducing DVD videos.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example of a configuration ofa digital television receiver including a DVD drive according to thepresent invention;

FIG. 2 is a block diagram illustrating an example of a configuration ofthe copyright protection circuit shown in FIG. 1; and

FIG. 3 is a flow chart illustrating the operation of the digitaltelevision receiver including the DVD drive.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, an example of a configuration of a digitaltelevision receiver including a built-in DVD drive according to thepresent invention is shown. In the digital television receiver 1 havingthe built-in DVD drive, a receiving circuit 3 receives a digitaltelevision broadcast wave (satellite or terrestrial digital broadcastwave) via an antenna 2 and extracts a signal (AV data coded in acompressed form according to the MPEG-2 standard) corresponding to aselection command given by a control circuit 18. The resultant signal issupplied to a demultiplexer (DMUX) 4. The demultiplexer 4 separates thesignal received from the receiving circuit 3 into a video signal codedin the compressed form, an audio signal coded in the compressed form,and copyright protection information (waveform information and an APS(analog protection system) signal). These resultant signals are suppliedto a switching circuit 8.

A reproducing circuit 6 reads a signal (AV data coded in a compressedform according to the MPEG-2 standard) recorded on a DVD 5 in responseto a reproducing command given by the control circuit 18. The resultantsignal is sent to a demultiplexer (DMUX) 7. The demultiplexer 7separates the signal received from the reproducing circuit 6 into avideo signal coded in the compressed form, an audio signal coded in thecompressed form, and copyright protection information. These resultantsignals are supplied to the switching circuit 8.

Under the control of the control circuit 18, the switching circuit 8selects a video signal coded in the compressed form, an audio signalcoded in the compressed form, and copyright protection informationoutput from either the demultiplexer 4 or 7, and outputs them to a videosignal decoding circuit 12, an audio signal decoding circuit 13, and acopyright protection circuit 9, respectively.

In accordance with the copyright protection information received fromthe switching circuit 8, the copyright protection circuit 9 generates asignal which allows the copyright of the AV data to be protected (thatis, which limits the copying of the AV data).

FIG. 2 illustrates an example of a detailed configuration of thecopyright protection circuit 9. In FIG. 2, a CGMS signal generator 21generates a CGMS (copy generation management system) signal inaccordance with the wave information contained in the copyrightprotection information and outputs it to an insertion circuit 10. TheCGMS signal refers to a 2-bit signal which controls a DV (digital video)recorder so as to limit the number of times that the AV data includingthe CGMS signal is copied. The CMGS signal can have one of four values:00, 10, 01, and 11, which indicate “Copyfree”, “Copyonce”, “AlreadyCopied”, and “Never Copy”, respectively.

An AGC pulse output circuit 22 generates an AGC (automatic gain control)pulse signal in accordance with an APS (a signal indicating whether ornot analog copying is allowed) contained in the copyright protectioninformation and outputs the resultant signal to the insertion circuit10. The AGC pulse signal refers to a signal which controls a VHS videocassette recorder so as to prevent AGC processing (prevent the AV datafrom being copied in a normal fashion).

A color stripe output circuit 23 generates a color stripe signal inaccordance with the APS signal contained in the copyright protectioninformation and outputs it to the insertion circuit 10. The color stripesignal refers to a signal which controls a VHS video cassette recorderso as to insert color stripes into a recorded image (thereby preventingthe image from being copied in a normal fashion).

Referring again to FIG. 1, the insertion circuit 10 inserts the CGMSsignal, the AGC pulse signal, and the color stripe signal supplied fromthe copyright protection circuit 9 into the video signal decoded by thevideo signal decoding circuit 12, within a V blank period thereof, andoutputs the resultant video signal to an external output terminal 11 a,a display 14, and a recording circuit 16. The external output terminal11 is connected to, for example, a VHS video cassette recorder (notshown).

The video signal decoding circuit 12 decodes the video signal coded inthe compressed form, supplied from the switching circuit 8, and outputsthe decoded video signal to the insertion circuit 10. The audio signaldecoding circuit 13 decodes the audio signal coded in the compressedform, supplied from the switching circuit 8, and outputs the decodedaudio signal to the external output terminal 11 b, a loudspeaker 15, andthe recording circuit 16.

The display 14 displays the image of the decoded video signal suppliedfrom the insertion circuit 10. Although the decoded video signal outputfrom the insertion circuit 10 includes the CGMS signal and otherprotection control signals, those protection control signals do not actupon the display 14 and thus do not affect the image displayed thereon.

The loudspeaker 15 emits an audio signal decoded by the audio signaldecoding circuit 13.

In accordance with the control signal output from the control circuit18, the recording circuit 16 codes the video signal received from theinsertion circuit 10 (that is, the video signal received, decoded, andadded with the CGMS signal in the V blank period by the antenna 2) andthe audio signal received from the audio signal decoding circuit 13(that is, the audio signal received and decoded by the antenna 12) inaccordance with the MPEG-2 standard and records them on the DVD 5.

A remote controller 17 includes a plurality of buttons (not shown) usedby a user to issue commands to receive and select a digital televisionbroadcast station and to reproduce or record data from or onto the DVD5. The operation performed by the user upon a button is detected, and acorresponding operation command is applied to the control circuit 18. Inresponse to the operation command given from the remote controller 17,the control circuit 18 outputs control commands to various circuit partsas required.

The displaying operation of the digital television receiver includingthe built-in DVD drive is described below with reference to FIG. 3. Instep S1, if a user issues a command to select a digital televisionbroadcast channel or a command to reproduce a DVD 5 by pressing a buttonprovided on the remote controller 17, the remote controller 17 suppliesa corresponding operation command to the control circuit 18.

In step S2, the control circuit 18 determines whether the operationcommand input from the remote controller 17 is a command to select adigital television broadcast channel or a command to reproduce the DVD5. If it is determined that the input command is a command to select adigital television broadcast channel, then the operation goes to stepS3.

In step S3, the control circuit 18 outputs a control command to thereceiving circuit 3 to control the switching circuit 8 such that thesignals output from the demultiplexer 4 are transferred to the circuitparts following the switching circuit 8. In response to this controlcommand, the receiving circuit 3 extracts a signal (AV data coded in thecompressed form according to the MPEG-2 standard) of the selectedchannel of digital television broadcast waves input via the antenna 2,and outputs the extracted signal to the demultiplexer 4. Thedemultiplexer 4 separates the signal received from the receiving circuit3 into a video signal coded in the compressed form, an audio signalcoded in the compressed form, and copyright protection information, andoutputs these signals to the switching circuit 8. Under the control ofthe control circuit 18, the switching circuit 8 outputs the video signalcoded in the compressed form, input from the demultiplexer 4, to thevideo signal decoding circuit 12, the audio signal coded in thecompressed form to the audio signal decoding circuit 13, and thecopyright protection information to the copyright protection circuit 9.

In step S5, the video signal decoding circuit 12 decodes the videosignal coded in the compressed form, received from the switching circuit8, and outputs the decoded video signal to the insertion circuit 10. Theaudio signal decoding circuit 13 decodes the audio signal coded in thecompressed form, applied from the switching circuit 8.

In step S6, the CGMS signal generator 21 generates a CGMS signal inaccordance with the wave information contained in the copyrightprotection information and outputs it to the insertion circuit 10. TheAGC pulse output circuit 22 generates an AGC pulse signal in accordancewith the APS contained in the copyright protection information andoutputs the resultant signal to the insertion circuit 10. The colorstripe output circuit 23 generates a color stripe signal in accordancewith the APS signal and outputs it to the insertion circuit 10. Theinsertion circuit 10 inserts the CGMS signal, the AGC pulse signal, andthe color stripe signal received from the copyright protection circuit 9into the video signal decoded by the video signal decoding circuit 12,within the V blank period thereof, and outputs the resultant videosignal to the external output terminal 11 a and the recording circuit16. In synchronization with the output of the video signal, the audiosignal decoding circuit 13 outputs the audio signal, decoded in step S5,to the external output terminal 11 b, the loudspeaker 15, and therecording circuit 16.

In step S7, the display 14 displays the image of the video signaldecoded by the video signal decoding circuit 12. The loudspeaker 15emits the audio signal decoded by the audio signal decoding circuit 13.

If it is determined in step S2 that the input command is a command toreproduce the DVD 5, then the operation goes to step S4.

In step S4, the control circuit 18 outputs a control command to thereproducing circuit 6 to control the switching circuit 8 such that thesignals output from the demultiplexer 7 are transferred to the circuitparts following the switching circuit 8. In response to this controlcommand, the reproducing circuit 6 reads a signal (AV data or the likecoded in the compressed form according to the MPEG-2 standard) from theDVD 5 and outputs it to the demultiplexer 7. The demultiplexer 7separates the signal received from the reproducing circuit 6 into avideo signal coded in the compressed form, an audio signal coded in thecompressed form, and copyright protection information, and outputs theseresultant signals to the switching circuit 8. Under the control of thecontrol circuit 18, the switching circuit 8 outputs the video signalcoded in the compressed form, input from the demultiplexer 7, to thevideo signal decoding circuit 12, the audio signal coded in thecompressed form to the audio signal decoding circuit 13, and thecopyright protection information to the copyright protection circuit 9.

Thereafter, step S5 and the following steps are performed.

In the digital television receiver 1 including the built-in DVD driveaccording to the preferred embodiment described above, unlike the casewhere a set top box for receiving a digital television broadcast and aDVD player are separately connected to a display, the MPEG decoder(including the video signal decoding circuit 12 and other parts) havinga relatively large circuit size, the power supply, and the housing areused in common, and thus reductions in the installation space and thecost are achieved and an increase in reliability is also achieved.Furthermore, users are not required to connect cables for transmittingsignals such as a video signal.

Furthermore, in the preferred embodiment, because the digital AV datacan be processed without needing conversion into analog form,degradation in the bandwidth of data and occurrences of cross-color anddot interference are suppressed, and thus the image quality is improved.

In the embodiment described above, when AV data of a digital televisionbroadcast is recorded on the DVD 5, the received AV data is firstdecoded into the decompressed form and then coded again into thecompressed form. Alternatively, the received AV data in the compressedform may be directly recorded, or the decoded AV data (in analog form)may be recorded.

The present invention may also be applied to other devices such as a settop box for digital cable television.

The computer program for performing the above-described process may besupplied to a user via an information recording medium such as amagnetic disk or a CD-ROM and also via a network medium such as theInternet and a digital satellite.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. A readable medium recorded with instructions for carrying out amethod for receiving digital television broadcast signals andreproducing AV signals in a common apparatus, said method comprising:receiving at least one operation command provided by a user; determiningwhether the received operation command is a command to select a digitaltelevision broadcast channel or a command to reproduce data; when thereceived operation command is a command to select a digital televisionbroadcast channel: receiving a digital television broadcast signal, andseparating the received digital television broadcast signal into a firstvideo signal coded in a compressed form according to a predeterminedmethod, a first audio signal coded in the compressed form, and firstcopyright protection information; when the received operation command isa command to reproduce data: reproducing an AV signal from a recordingmedium, and separating the reproduced signal into a second video signalcoded in the compressed form, a second audio signal coded in thecompressed form, and second copyright protection information; selectingthe first video signal, the first audio signal, and the first copyrightprotection information when the received operation command is thecommand to select the digital television broadcast channel and selectingthe second video signal, the second audio signal, and the secondcopyright protection information when the received operation command isthe command to reproduce data; decoding the selected video signal, theselected audio signal, and the selected copyright protection informationto generate a decoded video signal, a decoded audio signal, and acopyright protection signal; and adding the copyright protection signalto the decoded video signal and to the decoded audio signal to limit thecopying of the decoded video signal and the decoded audio signal.
 2. Areadable medium according to claim 1, wherein the predetermined methodis a method according to the MPEG-2 standard.
 3. A readable mediumaccording to claim 1, wherein the recording medium is a DVD.
 4. Areadable medium according to claim 1, wherein said method furthercomprises recording the received digital television broadcast signalonto the recording medium.
 5. A readable medium according to claim 1,wherein said method further comprises displaying an image based on thedecoded video signal and emitting sound based on the decoded audiosignal.